/******************************************************************************

Copyright (c) 2010, Cormac Flanagan (University of California, Santa Cruz)
                    and Stephen Freund (Williams College) 

All rights reserved.  

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the names of the University of California, Santa Cruz
      and Williams College nor the names of its contributors may be
      used to endorse or promote products derived from this software
      without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

******************************************************************************/

// based on ASM code

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.  
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package rr.instrument.analysis;

import java.io.FileInputStream;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.signature.SignatureReader;

/**
 * A {@link ClassVisitor} that prints a disassembled view of the classes it
 * visits. This class visitor can be used alone (see the {@link #main main}
 * method) to disassemble a class. It can also be used in the middle of class
 * visitor chain to trace the class that is visited at a given point in this
 * chain. This may be uselful for debugging purposes. <p> The trace printed when
 * visiting the <tt>Hello</tt> class is the following: <p> <blockquote>
 * 
 * <pre>
 * // class version 49.0 (49)
 * // access flags 33
 * public class Hello {
 *
 *  // compiled from: Hello.java
 *
 *   // access flags 1
 *   public &lt;init&gt; ()V
 *     ALOAD 0
 *     INVOKESPECIAL java/lang/Object &lt;init&gt; ()V
 *     RETURN
 *     MAXSTACK = 1
 *     MAXLOCALS = 1
 *
 *   // access flags 9
 *   public static main ([Ljava/lang/String;)V
 *     GETSTATIC java/lang/System out Ljava/io/PrintStream;
 *     LDC &quot;hello&quot;
 *     INVOKEVIRTUAL java/io/PrintStream println (Ljava/lang/String;)V
 *     RETURN
 *     MAXSTACK = 2
 *     MAXLOCALS = 1
 * }
 * </pre>
 * 
 * </blockquote> where <tt>Hello</tt> is defined by: <p> <blockquote>
 * 
 * <pre>
 * public class Hello {
 *
 *     public static void main(String[] args) {
 *         System.out.println(&quot;hello&quot;);
 *     }
 * }
 * </pre>
 * 
 * </blockquote>
 * 
 * @author Eric Bruneton
 * @author Eugene Kuleshov
 */
public class TraceClassVisitor extends TraceAbstractVisitor implements
        ClassVisitor
{

    /**
     * The {@link ClassVisitor} to which this visitor delegates calls. May be
     * <tt>null</tt>.
     */
    protected final ClassVisitor cv;

    /**
     * Prints a disassembled view of the given class to the standard output. <p>
     * Usage: TraceClassVisitor [-debug] &lt;fully qualified class name or class
     * file name &gt;
     * 
     * @param args the command line arguments.
     * 
     * @throws Exception if the class cannot be found, or if an IO exception
     *         occurs.
     */
    public static void main(final String[] args) throws Exception {
        int i = 0;
        int flags = ClassReader.SKIP_DEBUG;

        boolean ok = true;
        if (args.length < 1 || args.length > 2) {
            ok = false;
        }
        if (ok && args[0].equals("-debug")) {
            i = 1;
            flags = 0;
            if (args.length != 2) {
                ok = false;
            }
        }
        if (!ok) {
            System.err.println("Prints a disassembled view of the given class.");
            System.err.println("Usage: TraceClassVisitor [-debug] "
                    + "<fully qualified class name or class file name>");
            return;
        }
        ClassReader cr;
        if (args[i].endsWith(".class") || args[i].indexOf('\\') > -1
                || args[i].indexOf('/') > -1)
        {
            cr = new ClassReader(new FileInputStream(args[i]));
        } else {
            cr = new ClassReader(args[i]);
        }
        cr.accept(new TraceClassVisitor(null),
                getDefaultAttributes(),
                flags);
    }

    /**
     * Constructs a new {@link TraceClassVisitor}.
     * 
     * @param cv the {@link ClassVisitor} to which this visitor delegates calls.
     *        May be <tt>null</tt>.
     * @param pw the print writer to be used to print the class.
     */
    public TraceClassVisitor(final ClassVisitor cv) {
        this.cv = cv;
    }

    // ------------------------------------------------------------------------
    // Implementation of the ClassVisitor interface
    // ------------------------------------------------------------------------

    public void visit(
        final int version,
        final int access,
        final String name,
        final String signature,
        final String superName,
        final String[] interfaces)
    {
        int major = version & 0xFFFF;
        int minor = version >>> 16;
        buf.setLength(0);
        buf.append("// class version ")
                .append(major)
                .append('.')
                .append(minor)
                .append(" (")
                .append(version)
                .append(")\n");
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            buf.append("// DEPRECATED\n");
        }
        buf.append("// access flags ").append(access).append('\n');

        appendDescriptor(CLASS_SIGNATURE, signature);
        if (signature != null) {
            TraceSignatureVisitor sv = new TraceSignatureVisitor(access);
            SignatureReader r = new SignatureReader(signature);
            r.accept(sv);
            buf.append("// declaration: ")
                    .append(name)
                    .append(sv.getDeclaration())
                    .append('\n');
        }

        appendAccess(access & ~Opcodes.ACC_SUPER);
        if ((access & Opcodes.ACC_ANNOTATION) != 0) {
            buf.append("@interface ");
        } else if ((access & Opcodes.ACC_INTERFACE) != 0) {
            buf.append("interface ");
        } else if ((access & Opcodes.ACC_ENUM) == 0) {
            buf.append("class ");
        }
        appendDescriptor(INTERNAL_NAME, name);

        if (superName != null && !superName.equals("java/lang/Object")) {
            buf.append(" extends ");
            appendDescriptor(INTERNAL_NAME, superName);
            buf.append(' ');
        }
        if (interfaces != null && interfaces.length > 0) {
            buf.append(" implements ");
            for (int i = 0; i < interfaces.length; ++i) {
                appendDescriptor(INTERNAL_NAME, interfaces[i]);
                buf.append(' ');
            }
        }
        buf.append(" {\n\n");

        addText(buf.toString());

        if (cv != null) {
            cv.visit(version, access, name, signature, superName, interfaces);
        }
    }

    public void visitSource(final String file, final String debug) {
        buf.setLength(0);
        if (file != null) {
            buf.append(tab)
                    .append("// compiled from: ")
                    .append(file)
                    .append('\n');
        }
        if (debug != null) {
            buf.append(tab)
                    .append("// debug info: ")
                    .append(debug)
                    .append('\n');
        }
        if (buf.length() > 0) {
            addText(buf.toString());
        }

        if (cv != null) {
            cv.visitSource(file, debug);
        }
    }

    public void visitOuterClass(
        final String owner,
        final String name,
        final String desc)
    {
        buf.setLength(0);
        buf.append(tab).append("OUTERCLASS ");
        appendDescriptor(INTERNAL_NAME, owner);
        buf.append(' ');
        if (name != null) {
            buf.append(name).append(' ');
        }
        appendDescriptor(METHOD_DESCRIPTOR, desc);
        buf.append('\n');
        addText(buf.toString());

        if (cv != null) {
            cv.visitOuterClass(owner, name, desc);
        }
    }

    @Override
	public AnnotationVisitor visitAnnotation(
        final String desc,
        final boolean visible)
    {
        addText("\n");
        AnnotationVisitor tav = super.visitAnnotation(desc, visible);
        if (cv != null) {
            ((TraceAnnotationVisitor) tav).av = cv.visitAnnotation(desc,
                    visible);
        }
        return tav;
    }

    @Override
	public void visitAttribute(final Attribute attr) {
        addText("\n");
        super.visitAttribute(attr);

        if (cv != null) {
            cv.visitAttribute(attr);
        }
    }

    public void visitInnerClass(
        final String name,
        final String outerName,
        final String innerName,
        final int access)
    {
        buf.setLength(0);
        buf.append(tab).append("// access flags ");
        buf.append(access & ~Opcodes.ACC_SUPER).append('\n');
        buf.append(tab);
        appendAccess(access);
        buf.append("INNERCLASS ");
        appendDescriptor(INTERNAL_NAME, name);
        buf.append(' ');
        appendDescriptor(INTERNAL_NAME, outerName);
        buf.append(' ');
        appendDescriptor(INTERNAL_NAME, innerName);
        buf.append('\n');
        addText(buf.toString());

        if (cv != null) {
            cv.visitInnerClass(name, outerName, innerName, access);
        }
    }

    public FieldVisitor visitField(
        final int access,
        final String name,
        final String desc,
        final String signature,
        final Object value)
    {
        buf.setLength(0);
        buf.append('\n');
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            buf.append(tab).append("// DEPRECATED\n");
        }
        buf.append(tab).append("// access flags ").append(access).append('\n');
        if (signature != null) {
            buf.append(tab);
            appendDescriptor(FIELD_SIGNATURE, signature);

            TraceSignatureVisitor sv = new TraceSignatureVisitor(0);
            SignatureReader r = new SignatureReader(signature);
            r.acceptType(sv);
            buf.append(tab)
                    .append("// declaration: ")
                    .append(sv.getDeclaration())
                    .append('\n');
        }

        buf.append(tab);
        appendAccess(access);

        appendDescriptor(FIELD_DESCRIPTOR, desc);
        buf.append(' ').append(name);
        if (value != null) {
            buf.append(" = ");
            if (value instanceof String) {
                buf.append("\"").append(value).append("\"");
            } else {
                buf.append(value);
            }
        }

        buf.append('\n');
        addText(buf.toString());

        TraceFieldVisitor tav = createTraceFieldVisitor();

        if (cv != null) {
            tav.fv = cv.visitField(access, name, desc, signature, value);
        }

        return tav;
    }

    public MethodVisitor visitMethod(
        final int access,
        final String name,
        final String desc,
        final String signature,
        final String[] exceptions)
    {
        buf.setLength(0);
        buf.append('\n');
        if ((access & Opcodes.ACC_DEPRECATED) != 0) {
            buf.append(tab).append("// DEPRECATED\n");
        }
        buf.append(tab).append("// access flags ").append(access).append('\n');

        if (signature != null) {
            buf.append(tab);
            appendDescriptor(METHOD_SIGNATURE, signature);

            TraceSignatureVisitor v = new TraceSignatureVisitor(0);
            SignatureReader r = new SignatureReader(signature);
            r.accept(v);
            String genericDecl = v.getDeclaration();
            String genericReturn = v.getReturnType();
            String genericExceptions = v.getExceptions();

            buf.append(tab)
                    .append("// declaration: ")
                    .append(genericReturn)
                    .append(' ')
                    .append(name)
                    .append(genericDecl);
            if (genericExceptions != null) {
                buf.append(" throws ").append(genericExceptions);
            }
            buf.append('\n');
        }

        buf.append(tab);
        appendAccess(access);
        if ((access & Opcodes.ACC_NATIVE) != 0) {
            buf.append("native ");
        }
        if ((access & Opcodes.ACC_VARARGS) != 0) {
            buf.append("varargs ");
        }
        if ((access & Opcodes.ACC_BRIDGE) != 0) {
            buf.append("bridge ");
        }

        buf.append(name);
        appendDescriptor(METHOD_DESCRIPTOR, desc);
        if (exceptions != null && exceptions.length > 0) {
            buf.append(" throws ");
            for (int i = 0; i < exceptions.length; ++i) {
                appendDescriptor(INTERNAL_NAME, exceptions[i]);
                buf.append(' ');
            }
        }

        buf.append('\n');
        addText(buf.toString());

        TraceMethodVisitor tcv = createTraceMethodVisitor();

        if (cv != null) {
            tcv.mv = cv.visitMethod(access, name, desc, signature, exceptions);
        }

        return tcv;
    }

    @Override
	public void visitEnd() {
        addText("}\n");

        if (cv != null) {
            cv.visitEnd();
        }
    }

    // ------------------------------------------------------------------------
    // Utility methods
    // ------------------------------------------------------------------------

    protected TraceFieldVisitor createTraceFieldVisitor() {
        return new TraceFieldVisitor();
    }

    protected TraceMethodVisitor createTraceMethodVisitor() {
        return new TraceMethodVisitor();
    }

    /**
     * Appends a string representation of the given access modifiers to {@link
     * #buf buf}.
     * 
     * @param access some access modifiers.
     */
    private void appendAccess(final int access) {
        if ((access & Opcodes.ACC_PUBLIC) != 0) {
            buf.append("public ");
        }
        if ((access & Opcodes.ACC_PRIVATE) != 0) {
            buf.append("private ");
        }
        if ((access & Opcodes.ACC_PROTECTED) != 0) {
            buf.append("protected ");
        }
        if ((access & Opcodes.ACC_FINAL) != 0) {
            buf.append("final ");
        }
        if ((access & Opcodes.ACC_STATIC) != 0) {
            buf.append("static ");
        }
        if ((access & Opcodes.ACC_SYNCHRONIZED) != 0) {
            buf.append("synchronized ");
        }
        if ((access & Opcodes.ACC_VOLATILE) != 0) {
            buf.append("volatile ");
        }
        if ((access & Opcodes.ACC_TRANSIENT) != 0) {
            buf.append("transient ");
        }
        if ((access & Opcodes.ACC_ABSTRACT) != 0) {
            buf.append("abstract ");
        }
        if ((access & Opcodes.ACC_STRICT) != 0) {
            buf.append("strictfp ");
        }
        if ((access & Opcodes.ACC_ENUM) != 0) {
            buf.append("enum ");
        }
    }
}
